A systems administrator wants to leverage their password-protected SSH key to connect to multiple servers without entering their password every time. Which of the following commands should the…

ssh-copy-id is used to copy a public SSH key to a remote server's authorized_keys file, enabling passwordless login to that server, but it does not manage the passphrase for a local private key.

ssh-agent is the background program that holds the private keys and performs authentication, but ssh-add is the command used to load keys into the agent, not ssh-agent itself.

The ssh-add command adds private key identities to the authentication agent (ssh-agent). When a password-protected SSH key is added to the ssh-agent using ssh-add, the passphrase only needs to be entered once, and the agent handles subsequent authentication requests.

ssh-keygen is used to generate new SSH key pairs (public and private keys), not to manage existing keys with an agent.